Touch doesn't work in Windows 10 file open picker

Question

I've downloaded the file open picker sample from microsoft (https://code.msdn.microsoft.com/windowsapps/File-picker-app-extension-0cb95155) for testing the file open picker contract.

I installed the sample app and then went through the file picker UI (where I get to select the installed app to pick a file from). From there I can't interact with the UI using the touch screen. The mouse works fine. The sample works fine with touch in Windows 8.1.

It only ignores the click events. The hover animations still happen.

I also made a really simple app with just a GridView and a Button. GridView.ItemClick worked fine with touch, but the button click events would only work maybe once every 30 clicks. I tried setting Click, PointerReleased, and Command.

I tried the built-in photo app, and get the same results. Touch doesn't work for buttons outside of the GridView.

Here's my simple page (minus the GridView) that doesn't respond well to touch click events:

public sealed partial class App : Application
{
        ...
        protected override void OnFileOpenPickerActivated(FileOpenPickerActivatedEventArgs args)
        {
            var root = new Frame();
            Window.Current.Content = root;
            root.Navigate(typeof(MainPage), null);
            Window.Current.Activate();
            base.OnFileOpenPickerActivated(args);
        }
        ...
}

<Page
    x:Class="FilePickerTest.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:FilePickerTest"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d">

    <Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
        <Button Content="Sample"
                Width="400"
                Height="100"
                Click="Button_Click"/>
    </Grid>
</Page>

Anyone else notice this and come up with a workaround?